Answer:
x = - 1
Step-by-step explanation:
Because this a vertically opening parabola, then the axis of symmetry is a vertical line with equation
x = c
where c is the value of the x- coordinates the line passes through.
The axis of symmetry passes through the vertex (- 1, 16) with x- coordinate - 1
Thus the equation of the axis of symmetry is x = - 1
